Lithography is considered as a key technique in semiconductor manufacturing processes, e.g., in manufacturing large scale integrated circuits (LSI). Lithography often includes a process for transferring patterns from a mask to a substrate by an exposure process. During semiconductor manufacturing processes, a series of complex and time-consuming lithography processes are performed mainly by corresponding exposure devices. Development of lithography technology or exposure devices has been made around three main factors including line widths, overlay accuracy, and production yields.
The exposure process often includes three steps: loading a substrate on a stage; aligning the substrate on the stage; and transferring a pattern from a mask to the substrate. The three steps are performed successively and repeatedly on the same stage. Because lithography is a key process in semiconductor manufacturing processes, it is important to improve production yields of the exposure devices in mass production. Conventional methods for improving production yields of the exposure devices include use of twin stages in exposure devices to simultaneously perform the above-described steps of loading, aligning, and transferring in the exposure process.
However, it is difficult to accurately control and match positions of the twin stages in conventional exposure devices. In addition, conventional calibration processes are complex, which may affect accuracy (e.g., overlay accuracy) of the exposure devices and generate inconveniences in use.
Therefore, there is a need to provide an exposure device that has improved accuracy and is convenient in use, and also to provide an exposure method.